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One thought on “Objects, or not? Corrections appreciated…”

In all your examples both can be said . The literary or proper form includes “le” and lazy common form finds it’s too heavy to carry on one’s mouth .
I don’t understand the title; the question is not “objects or not” but “direct objects or not” . In “je vais te l’expliquer” “te” is the indirect object and “le” the direct : Je vais expliquer “le” à “toi” ; “je te l’ai déjà dit”= j’ai déjà dit “le” à “toi” . What doesn’t need any preposition and answers the question ” tu as dit quoi” or “tu as vu qui”is a direct object. If you need a preposition it can be an indirect object or something else .
For French grammar one needs to “unroll” the phrase, as Idid above twice, to find the proper agreement or syntax . It is often useful and especially for agreements with past participles of pronominal verbs .